1. Field of the Invention:
The present invention relates to a sound processing device for processing sound.
2. Description of the Related Art:
A sound recording device for converting sound into an electrical signal through a microphone or the like to form an audio signal and recording the formed audio signal on a recording medium by a tape recorder or the like has heretofore been known as one kind of device for processing sound.
In such a sound recording device, it is customary to use an audio-signal amplifying circuit having a substantially fixed frequency characteristic for amplifying the audio signal generated from the microphone. In this arrangement, if wind or the like blows against the microphone, noise due to the wind is introduced into sound to be recorded and the audio signal is degraded. For this reason, a wind screen or the like has conventionally been attached to the microphone to prevent the influence of the wind.
Because of the frequency characteristic of the aforesaid noise due to wind, which is a signal of low frequency, it has recently been proposed to provide an arrangement with a selecting switch for selectively switching frequency characteristics so that a low-frequency component can be eliminated from an audio signal. If wind is blowing during photography, an operator operates the selecting switch to actuate the audio-signal amplifying circuit to eliminate the low-frequency component from the audio signal so as to eliminate the influence of the wind.
However, the arrangement of the aforesaid device which uses the wind screen to prevent the influence of wind has the problem that the size of the device increases.
The arrangement in which an operator arbitrarily operates the selecting switch to actuate the audio signal amplifying circuit to eliminate the low-frequency component from the audio signal so as to prevent the influence of wind has the problem that it is very difficult for the operator to correctly determine whether wind is blowing and operate the selecting switch. There is also the possibility that the operator may erroneously operate the selecting switch.
In other words, to determine how the influence of the wind is, the operator needs to monitor the sound collected by the microphone at all times during photography. Such an arrangement is awkward for the operator to use.
If the operator operates the selecting switch without monitoring sound, a number of problems will occur. For example, while wind is blowing against the microphone, if the operator does not operate the selecting switch to eliminate the low-frequency component of the audio signal generated from the microphone, the level of noise due to the wind becomes high compared to the level of sound to be recorded. As a result, an AGC (Automatic Gain Controller) in the audio signal amplifying circuit may operate to lower the level of the entire sound collected by the microphone, by the influence of the noise due to the wind. While wind is not blowing against the microphone, if the operator erroneously operates the selecting switch to eliminate the low-frequency component of the audio signal, the low-frequency component of the sound collected by the microphone will be eliminated consistently during photography, with the result that the quality of the sound to be recorded is impaired.